1. Field of the Invention
This invention, in certain aspects, is directed to power systems; such plants that use methanol in a feedstock; and to methods using such systems to produce electricity.
2. Description of Related Art
The prior art discloses a wide variety of plants and apparatuses for generating electricity using gas turbines. U.S. Pat. No. 4,148,185 discusses the generation of power from the combustion of hydrogen and oxygen cryogenic propellants for the electrolytic release of hydrogen from water to produce oxygen which can also be stored for subsequent combustion to generate power when needed. The separately stored oxygen and hydrogen are combusted together in the presence of a combustion flame coolant (water) to develop a motive fluid (steam) which is first passed through a heat exchanger and then to a turbine inlet. The motive fluid is exhausted from the turbine and reheated in the heat exchanger via the first passage therethrough and then delivered to the inlet of a second turbine. It is then exhausted into a condenser producing waste heat with a portion being re-introduced into the combustor for again cooling the combustion process. Such a system has a motive fluid inlet temperature of 2100xc2x0 F. or above (a typical gas turbine inlet temperature), the inlet temperature to the preceding heat exchanger is at least as high as the initial inlet temperature to the first turbine plus the temperature rise required in the heat exchanger to raise the exhaust motive fluid from the first turbine to the inlet temperature of the second turbine. With the present turbine inlet temperatures being in the range of 2100xc2x0, the heat exchanger inlet temperature is up to 3,000xc2x0 F. This temperature requirement places design restrictions on the heat exchanger that are difficult to accommodate economically and still provide the long-life expected of equipment in power generating systems.
U.S. Pat. No. 4,148,185 discloses a gas turbine power generation system using high pressure hydrogen and oxygen as the fuel for the gas turbines with the combustion process cooled by the introduction of water or steam so that the combustion temperature range is acceptable. A series of gas turbine engines are connected in series-flow communication so that the reheat of the motive fluid (the combustion of oxygen and hydrogen producing a motive fluid of steam) for the second and subsequent turbines of the system is accomplished by directing the exhaust steam of the preceding turbine into the next downstream combustor wherein the steam is reheated by the combustion therein to the next turbine inlet temperature. Such reheating process can continue for sufficient stages until the pressure of the steam exhaust is at generally atmospheric pressure. The steam is finally exhausted through a heat exchanger to pre-heat the pressurized coolant water to at least partially convert it to steam (which conversion is completed by the combustion in the first combustion chamber or by a two-stage combustion therein) for entry into the initial combustor to cool the combustion process. The use of the combination reheat and the exhaust recuperation in the gas turbine system with hydrogen and oxygen as the combustion fuels maintains the temperature on the various parts, including the rotating members of the turbine engines, within acceptable limits for long-life operation and also increases the efficiency of the over-all power generation system.
U.S. Pat. No. 5,622,043 discloses an electric power generation with a gas turbine subsystem free of a compressor; a compressor subsystem with an air heater remote from the gas turbine subsystem having an inlet receiving air and an outlet furnishing heated compressed air after heating by the air heater; and a compressed air line interlinking the outlet and said gas turbine subsystem; the gas turbine subsystem having a plenum connected to the compressed air line; a burn chamber having a compressed air inlet connected to the plenum and a fuel inlet; a gas expander connected to the burn chamber; and an electrical generator connected to the gas expander; a steam generator having a heat inlet connected to the gas expander and a steam outlet; a first steam turbine having a steam inlet connected to the steam outlet; and a drive shaft connected to the electrical generator.
The present invention, in certain embodiments, discloses a system and method for producing electrical power, the method, in certain aspects, including feeding a mixture of water and methanol to a vaporizer, forming vapor with the vaporizer, the vapor including vaporized water and methanol, feeding vapor to a reformer, the reformer forming a first exit stream, the first exit stream including hydrogen, carbon dioxide, and steam, feeding the first exit stream from the reformer to a combustor and with the combustor combusting the first exit stream, producing hot gas (e.g. hot carbon dioxide and steam) and feeding it to power a turbine, the turbine for driving an electrical generator to produce electrical power, and thus producing electrical power.
Such a system and method may include, in certain aspects, a feed mixture of water and methanol with water between 65% and 75% by volume and methanol between 25% and 35% by volume. In one particular system there are 2 gallons of water to 1 gallon of methanol. Such a system and method may include, in certain aspects, a reformer that produces a second exit stream of steam (pure water) and, in certain aspects the second exit stream is fed to another apparatus, e.g., but not limited to, a boiler that produces steam. The boiler feed is, preferably, pure water that does not need to be further purified and/or chemically treated. In other aspects, the turbine has an exhaust and heat is extracted from the exhaust of the turbine which, in one particular aspect, is applied to the reformer. The steam produced by the boiler can be used to run, e.g., a power-producing apparatus, e.g. a turbine.
It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:
New, useful, unique, efficient, nonobvious systems and methods for producing electrical power;
Such apparatuses and methods which use a water/methanol mixture as an initial feed;
Such apparatuses and methods in which a stream with hydrogen, carbon dioxide, and water is combusted in a combustor associated with a power-producing turbine;
Such apparatuses and methods in which the combustor produces a stream of carbon dioxide and steam for driving a gas turbine which in turn drives an electrical generator to produce electrical power;
Such apparatuses and methods in which heat in the exhaust from a turbine is recaptured for use in the system; and
Such apparatuses, systems, and methods in which pure water is produced which, in one aspect, is re-used in the system.
Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures and functions. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.
The present invention recognizes and addresses the previously-mentioned problems and long-felt needs and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one skilled in this art who has the benefits of this invention""s realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent""s object to claim this invention no matter how others may later disguise it by variations in form or additions of further improvements.